Bump karma-coverage from 2.0.1 to 2.0.3 in /build

Bumps [karma-coverage](https://github.com/karma-runner/karma-coverage) from 2.0.1 to 2.0.3.
- [Release notes](https://github.com/karma-runner/karma-coverage/releases)
- [Changelog](https://github.com/karma-runner/karma-coverage/blob/master/CHANGELOG.md)
- [Commits](karma-runner/karma-coverage@v2.0.1...v2.0.3)

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